1. Field of the Invention
The present invention has to do with mechanically embossed resilient surface coverings. More particularly, the invention relates to resilient floorcovering having a photopolymer coating which is mechanically embossed and has a superior fidelity of texture which has not been achieved in previously known resilient products. In a preferred embodiment, the product is chemically embossed before it is mechanically embossed.
2. Description of the Related Art
Resilient surface coverings including sheet flooring, tile and wall covering are employed in residential, commercial and institutional applications where decorative effects, durability and ease of installation and maintenance are important considerations. The product can be designed to imitate other materials such as ceramic tile, wood, stone and brick, and straw, linen textiles, cork and the like, or it can be designed with unique combinations of color, particles and other decorative features which are not available in other types of surface coverings. In the current marketplace, consumers are increasingly demanding surface coverings with improved textural features, especially features which realistically imitate the textures of materials such as ceramic tile, wood, stone and brick, and straw, linen textiles, cork and the like. The surface covering industry has employed mechanical embossing, chemical embossing, a combination of mechanical and chemical embossing, screen printing and other techniques for decades in order to obtain design effects and textures which meet consumer demands.
The present invention is especially directed to the realistic imitation of surface textures from various kinds of floor and wall covering materials by employing materials and methods which can be used in new combinations with previously known materials and methods. The invention is applicable to surface coverings which can be coated with a photopolymer and mechanically embossed, particularly resilient sheet flooring, tile, wall covering and the like.
In accordance with this invention, a resilient surface covering is prepared with a plastic top layer and this layer is coated with a photopolymer. The photopolymer is subjected to heat, partial ultraviolet (UV) curing or ambient air so that it is dried but still thermoplastic (i.e., not cured). Then the surface is heated to soften the plastic top layer and the thermoplastic photopolymer. The softened surface is mechanically embossed followed by UV curing of the photopolymer. The product can be cooled before or after UV curing. The mechanically embossed product has a fidelity of texture which is superior to the textures obtained with previously known chemical and/or mechanical embossing and products which are urethane coated following embossing. The process of the invention also improves production yields by reducing the amount of product that needs to be scrapped due to defects in the polyurethane layer caused by unevenness, variations in gloss and the like.
In a preferred embodiment, a chemically embossed resilient flooring product is made by conventional means. When the product exits the fusion oven or a laminating unit, the wearlayer temperature is lowered. A water borne photopolymer polyurethane (PU) coating is then applied to the wearlayer and dried. Heat is applied to swell the surface (i.e., to soften the wearlayer and the PU layer) and the softened surface is mechanically embossed. Following this step, the material is either cooled down and then UV cured or it is UV cured followed by cooling. The material is taken up on large rolls for inspection and packaging. The process is modified as appropriate for other resilient surface coverings, depending upon their constriction, as will be described in more detail below.